A summary of May 4 events related to the vast oil spill from the Deepwater Horizon

Events May 4, Day 15 of a Gulf of Mexico oil spill that began with an explosion and fire on April 20 on the drilling rig Deepwater Horizon, owned by Transocean Ltd. and leased by BP PLC, which is in charge of cleanup and containment. The blast killed 11 workers. Since then, oil has been pouring into the Gulf from a blown-out undersea well at about 210,000 gallons per day. The slick threatens the U.S. coastline.

SMOOTH SEAS & A RETURN TO OFFSHORE CLEANUP

Winds calmed Tuesday after days of storms, letting cleanup crews return to work in the Gulf, cleaning oily water from a vast spill into skimmer boats, dropping dispersant on it, and rounding up some of the thickest oil to set ablaze.

Shoreline crews were laying more protective boom and repairing boom broken by the storms, said Doug Suttles, chief operating officer of BP PLC, which leased the rig.

"We do have the gift of time. It's a gift of a little bit of time. I'm not resting," said Coast Guard Rear Adm. Mary Landry.

She said 22 boats, 12 of them fishing boats, went to look for a sheen reported at Chandeleur Island but did not find one.

The Associated Press reported Thursday that some oil washed ashore at the mouth of the Mississippi River along the Louisiana coast. So far only sheens have reached some coastal waters.

A satellite image taken Sunday night indicated that the slick had shrunk from 3,400 square miles to 2,000, but it just meant that more was under water, said Hans Graber of the University of Miami.

Executives from BP PLC tell members of a congressional committee that in the worst-case scenario, a leaking well could spew up to 60,000 barrels of oil in the Gulf. Rep. Ed Markey, D-Mass., says industry officials told the House Energy and Commerce Committtee Tuesday the scenario translates to 2.5 million gallons a day. A more likely scenario if the leak gets worse is 40,000 barrels, or 1.7 million gallons.

LEAK CONTROL

Doug Suttles, chief operating officer of BP PLC, said the company hoped to shut off one of the smaller leaks Tuesday, with a valve set atop a bit of drilling pipe. "I don't think it will change the amount of oil," he said.

A 40-foot-tall "containment dome" — it actually looks rather like a child's drawing of a house made solid and stretched tall, with wide platforms halfway up — will be on the seabed Thursday, and hooked up to a drill ship over the weekend.

If it works, the 98-ton structure could funnel up to 85 percent of the oil to a ship.

Chemical dispersants piped 5,000 feet to the main leak have significantly reduced the amount of oil coming to the surface, one BP executive said. Suttles and the Coast Guard said results are encouraging but the technique is still being evaluated.

WILDLIFE

No oil was found on 29 dead turtles that washed onto the Mississippi coast over the past few days. But experts won't know until labs test tissue samples whether the turtles ate contaminated fish or jellyfish or came into contact with toxins from the oil.

Two birds found in the oil slick were recovering at a rescue center — a gannet found Friday and a brown pelican found sometime between then and Tuesday.

The U.S. Fish and Wildlife Service notes that a migratory bird "fall-out" near Gulf Breeze, Fla., happens every year as exhausted birds reach the U.S. coast after flying from South America.

FISHING DISASTER

The head of the Louisiana Charter Boat Association says the oil spill is a public relations disaster. Daryl Carpenter, a guide who was elected president of the 300-member association 17 days ago, says he's struggling to get Americans to understand that three-quarters of the Gulf is clean and open to fishing. He said Tuesday that people panicked by the media coverage are canceling trips as far out as July and August.

STATE AID

Suttles said BP has given $25 million grants to Louisiana, Mississippi, Alabama and Florida to help them pay for their cleanup work.

INVESTIGATIONS

Senate Commerce Committee Chairman Jay Rockefeller says he will hold a hearing on the Gulf oil spill in the coming weeks. The Senate Energy and Natural Resources Committee and the House Energy and Commerce Committee are both planning hearings.

Suttles said BP has its own investigation and he's sure rig owner Transocean LTD also has an internal investigation underway.

NATIONAL GUARD

The Pentagon said Defense Secretary Robert Gates has approved federal mobilization of up to 17,500 National Guard troops — up to 6,000 by Louisiana, 3,000 by Alabama, 2,500 by Florida and 6,000 by Mississippi. That means the states will control how the troops are used, and the federal government will pay.

PROTECTION

In St. Bernard Parish, La., National Guard troops were helping to load protective boom on boats going out into the marshes. Fishermen hope to boom off sensitive estuaries that are home to fish, crabs, shrimp, oysters and other marine animals before heavy oil tar-balls can reach the coast.

LAWSUITS

Three workers who escaped in lifeboats April 20 from the inferno on the Deepwater Horizon drilling platform sued companies involved, claiming they floated for more than 10 hours while the rig burned. The lawsuit, filed in county court in Galveston, Texas, seeks unspecified damages on behalf of Louisiana residents Joshua Kritzer, Bill Johnson and Nick Watson and the wife and two children of Aaron Dale Burkeen of Mississippi — one of 11 workers who were killed in the blast. At least two other wrongful death or personal injury suits were filed earlier.

LIABILITY

The White House pushes to lift the limit on how much BP pays for the Gulf Coast oil spill. Press Secretary Robert Gibbs said Tuesday the administration wants to work with Congress to change a law that caps at $75 million BP's liability for economic damages like lost wages or dwindling tourist dollars. BP PLC is responsible for all cleanup costs under the Oil Pollution Act, but Gibbs said that other costs could easily top $75 million.

THE PRESIDENT

President Barack Obama said working to contain environmental damage from the Gulf of Mexico oil spill poses a significant challenge to the nation and pledged to explore all options for replacing threatened jobs. He told a group of business leaders in Washington that the huge spill "is a reminder that the nation's economy can face a sudden and costly crisis at any time."

COASTAL DRILLING OPPOSITION INTENSIFIES

Congressional Democrats say the spill adds urgency to the troubled energy and climate overhaul bill working its way through the Senate. But concerns among other lawmakers leave the bill no clear path forward. Sen. Jay Rockefeller, D-W.Va., said, "Personally, I will have a very hard time ever voting for offshore drilling again. It's too much unknown."

The bill would curb pollution-causing gases blamed for global warming and crack down on oil companies, while it allowed drilling in new ocean areas along the coast of Alaska and the coast stretching from Delaware to Florida. But recent fatal accidents in the Gulf and a West Virginia coal mine have intensified the political cost-benefit analysis facing Congress and the White House.

DISASTER LOANS

Louisiana Gov. Bobby Jindal asked the federal Small Business Administration to make economic disaster loans available in six parishes to small businesses and private non-profits affected by the oil spill. The request covers Jefferson, Lafourche, Orleans, Plaquemines, St. Bernard and St. Tammany parishes.

Plaquemines Parish president Billy Nungesser says he's frustrated with a lack of information from the government in the aftermath of the Gulf oil spill. He says he's asked why the National Oceanic and Atmospheric Association can't provide better information.